Hide processor pipelines stat boxes during loading/empty state (#6983)

# Description of Changes

Gate the processor Pipelines KPI strip on having real pipelines, so the
loading and empty states no longer flash a row of empty `—` stat boxes.
Matches the Policies view; Sources is intentionally left as-is.

---

## Checklist

### General

- [x] I have read the [Contribution
Guidelines](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/CONTRIBUTING.md)
- [ ] I have read the [Stirling-PDF Developer
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/DeveloperGuide.md)
(if applicable)
- [ ] I have read the [How to add new languages to
Stirling-PDF](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/HowToAddNewLanguage.md)
(if applicable)
- [x] I have performed a self-review of my own code
- [x] My changes generate no new warnings

### Documentation

- [ ] I have updated relevant docs on [Stirling-PDF's doc
repo](https://github.com/Stirling-Tools/Stirling-Tools.github.io/blob/main/docs/)
(if functionality has heavily changed)
- [ ] I have read the section [Add New Translation
Tags](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/HowToAddNewLanguage.md#add-new-translation-tags)
(for new translation tags only)

### Translations (if applicable)

- [ ] I ran
[`scripts/counter_translation.py`](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/docs/counter_translation.md)

### UI Changes (if applicable)

- [ ] Screenshots or videos demonstrating the UI changes are attached
(e.g., as comments or direct attachments in the PR)

### Testing (if applicable)

- [x] I have run `task check` to verify linters, typechecks, and tests
pass
- [x] I have tested my changes locally. Refer to the [Testing
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/DeveloperGuide.md#7-testing)
for more details.

frontend/editor/src/portal/views/Pipelines.tsx

@@ -22,10 +22,12 @@ export function Pipelines() {
   const { isLoading } = useSectionFlags(state);
 
   const pipelines = data?.pipelines ?? [];
-  // Empty once the fetch settles with no pipelines (or fails → no data). Gates
-  // both the KPI strip and the empty panel so no placeholder stat boxes sit
-  // above an empty page.
+  // Empty once the fetch settles with no pipelines (or fails → no data); gates
+  // the empty panel below.
   const showEmpty = !isLoading && pipelines.length === 0;
+  // The KPI strip is pure stat boxes: show it only once real pipelines exist, so
+  // the loading and empty states don't flash a row of placeholder cards.
+  const hasPipelines = pipelines.length > 0;
 
   const openCreate = () =>
     navigate(`${toPortalPath(VIEW_PATHS.pipelines)}/new`);
@@ -54,7 +56,7 @@ export function Pipelines() {
         </Button>
       </header>
 
-      {!showEmpty && <KpiStrip data={data} loading={loading} />}
+      {hasPipelines && <KpiStrip data={data} loading={loading} />}
 
       {isLoading && (
         <div className="portal-pipelines__table-skeleton" aria-hidden>